Solenoids convert electrical energy into mechanical energy. Because of this phenomenon, solenoids are widely used in a variety of applications. Once such application is to use the solenoid as an actuator for operating a fuel injector of an internal combustion engine. However, as the engine becomes more and more dependent upon sophisticated electronics, it is desirable to detect and diagnose electrical problems. Since the solenoid is such a critical device, it is important to be able to detect its operability. One of the most common solenoid failures results from a shorted winding condition of the solenoid coil. Thus, it is desirable to detect such a condition.
Heretofore, detection of a shorted winding condition of the solenoid coil has been problematic. For example, one technique involves simply measuring the resistance across a test solenoid coil and comparing the measured resistance to a known resistance of a good coil. However, this technique does not produce accurate readings because the resistance change due to a few shorted coil windings is small and is difficult to detect. Another technique involves the use of a surge or ring testing device. This device places a high voltage pulse on a test solenoid coil. The resulting current oscillations are then displayed on an oscilloscope. The pattern of the test coil is compared with the pattern associated with a good coil. Unfortunately, this type of testing device is expensive and is not suitable in remote locations.
The present invention is directed to overcoming one or more of the problems as set forth above.